The present invention pertains to the field of communication. More particularly, this invention pertains to the field of optical fiber communication system.
Fiber optics has become one of the most important technologies in communication. It is both fast and reliable to use optical fiber in data transmission. Thus, optical fiber is widely utilized in high-speed telecom and datacom systems. These systems are made up of multiple components, including optical transponders. An optical transponder is a receiver-transmitter activated for transmission by reception of a predetermined signal in a fiber optic communication system, providing an interface between a photonic physical layer and an electrical section layer in the system.
Typically, an optical transponder includes an electrical driver that amplifies an optoelectric signal and drives it onto a transmission device. Prior art implementations of optical transponders use discrete components that include a driver and optical devices in separate packages. Discrete devices consume a lot of space and the performance of the resultant system is inefficient. However, in the prior art, putting the driver and the optical devices together in the same package is also undesirable because of high power consumption, typically 1.5W or greater. Thus, to improve performance and save space, which in turn reduces cost, a low power driver is desired that can be packaged together with other components of an optical transponder.
Prior-art high speed fiber-optic driver amplifiers utilize a transmission-line interface between the driver output and the laser diode input, which allows the two components to be physically separated by a moderate distance (few millimeters up to several centimeters for 10 Gb/s transmitters).
Another issue with a fiber optic communication system is the difficulty in scaling up and automating optical components in the system. The difficulties limit the bandwidth of a communication network.
A direct-drive modulator driver and an optical transponder incorporating the driver are described. The driver includes a transistor having a first terminal, a second terminal and a input terminal. The first terminal is grounded. The driver further includes a laser diode having a p-terminal and an n-terminal. The p-terminal is connected to a power supply, and the n-terminal is connected to the second terminal of the transistor. The driver further includes an input load connected to the input terminal of the transistor.
Other features and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description that follows below.